Need some Help on this 4hp Evinrude

Got this little 4hp Evinrude Model #4606W Serial #E0002381, I don't the exact date bu I know it's 70's.




As you can see it has a S/S and H/S adjustment knobs.

Well we've taken it out on our 14' Jon and it puttered around slowly just fin, but wenever we tried to push it , it would die. Then it would have a hard time starting. And sometimes it would just stay the same speed regardless of what the speed handle said. After doing some researc that the car needles control RPM's I assumed that they needed to be adjusted so I started from scratch and opened it the 1 1/2 (accurding to hat this site said) and everything was running surprisingly well until a woman walked by with her baby that started crying, I had to shut the motor off. I couldn't get it started afterwards. Any advice?

Also how hard would it be for me a pretty confdent DIY'er to clean the carb on this motor?

Re: Need some Help on this 4hp Evinrude

Very fine little motors they are. I have a 71. I would suggest you do a compression check first of all. If the compression is good then they are worth a bit of investment as far as new parts to get them running right for another generation. If compression is poor you may want to stop before spending any additional funds.

Cleaning the carb. is a straight forward enough job but I would suggest you purchase a new carb. kit from an Evinrude dealer. It will come with no instruction but it will include a new float among other things. The existing float will be made of cork and the cork is coated with shellac which breaks down with the newer blended gas. Anyway there are many things you should be doing/checking to a motor of that vintage to get it running trouble free again. But first thing to do is test your compression. Best of luck. Rick.

Re: Need some Help on this 4hp Evinrude

Rick. said:

Very fine little motors they are. I have a 71. I would suggest you do a compression check first of all. If the compression is good then they are worth a bit of investment as far as new parts to get them running right for another generation. If compression is poor you may want to stop before spending any additional funds.

Cleaning the carb. is a straight forward enough job but I would suggest you purchase a new carb. kit from an Evinrude dealer. It will come with no instruction but it will include a new float among other things. The existing float will be made of cork and the cork is coated with shellac which breaks down with the newer blended gas. Anyway there are many things you should be doing/checking to a motor of that vintage to get it running trouble free again. But first thing to do is test your compression. Best of luck. Rick.

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Thanks Rick. I'm pretty tight on money, how much does a new carb kit go for? As well how do you check the compression? I'm pretty novice when it comes to this.

Re: Need some Help on this 4hp Evinrude

4606 is a 1976 model

50:1 fuel mix. J6C plugs gapped at 0.030". Check ,clean and reset them or replace them if in doubt

Full details for adjusting the mixture knobs at http://forums.iboats.com/showthread.php?t=167352

Compression tester is a pressure reading gauge that screws in in place of the spark plugs.. May be able to hire, borrow or steal one.

remove both plugs and ground the leads, fit tester in one hole. pull starter several times to get the max reading, then do the other cyl. readings should be > 60 psi and within 10% of each other. >80psi better. > 120psi probably a defective gauge!


Mallory Carb kit 9-37106. A bit over $13 Lots of bits you may not need them all


But does not include the float!
OMC Part number 0375919 and another $10 if needed.

This Sierra carb kit from iBoats is also correct http://www.iboats.com/mall/partfind...&gd_poid=109333&gd_row=4&**********=016330379

Note a new kit will come with a little clip ( to the right of COM in the picture) that links the new type needle to the float arm.

Check/replace your gear case oil ( high visc outboard gear oil) Water or milkiness indicates a seal letting water in.

Check cooling. There is no telltale but you should get a few drops or a mist from the relief ports on the leg. You should be able to touch and maintain contact for 3 or 4 seconds any part of the power head except perhaps around the plugs and the exhaust manifold cover plate.

Replace pump impeller if in doubt or do it anyway if you do not know when it was last changed

Re: Need some Help on this 4hp Evinrude

Your motor will run better right side up. (lol)

Re: Need some Help on this 4hp Evinrude

Shrike said:

Your motor will run better right side up. (lol)

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Well I suppose someone had to say it!

I resisted the temptation!

Re: Need some Help on this 4hp Evinrude

Vic.S said:

Well I suppose someone had to say it!

I resisted the temptation!

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Those were just pictures i took of it when we got it. I'm gonna give the good advice you've given a shot. I honestly thought that motors ran that way for some reason, but I guess i could set it upright ya'll seem to know what you're talking about.

Re: Need some Help on this 4hp Evinrude

Money is always tight. That's why I suggested doing the compression check first. If it's bad then you probably won't want to put any money into it. Some auto supply stores lend out compression gauges. See if you can borrow one from them. There will be some expense involved if the compression checks out well. You may need new coils, carb. kit, plugs, gear case oil, points and condensers and certainly a good repair manual for reference. You will also need a few tools. I don't mean to scare you away. At the end of it all you should have a great running engine that will last a long time. I had mine out today and trolled for a few hours on less than a gallon of gas. It doesn't get any better than that. Rick.

Re: Need some Help on this 4hp Evinrude

I was planning on doing that compression test today and seeing what I got out of it, I read what you said earlier but I'm a little confused as tow hat I should be doing.

Re: Need some Help on this 4hp Evinrude

Also I adjusted the carb needles today for ****s and gigs. I got it running where I felt it need to be but the longer i ran it at full throttle it would eventually just die. The intrusctions for the high speed valve dont apply to mine because you can't open it a whol turn it only goes left for so far and right for so far, any suggestions?

Re: Need some Help on this 4hp Evinrude

Lehner said:

Also I adjusted the carb needles today for ****s and gigs. I got it running where I felt it need to be but the longer i ran it at full throttle it would eventually just die. The intrusctions for the high speed valve dont apply to mine because you can't open it a whol turn it only goes left for so far and right for so far, any suggestions?

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The knobs pull off and then you adjust the needles with a screwdriver. When they are set correctly put the knobs back on so that they are in the mid positions on the scales.

I think you need to sort out why it is dying before doing the adjustment. You may have a defective fuel pump or an air leak into the fuel line.
Try gently pumping the fuel line bulb. If that keeps it going then there is probably an air leak ( connector is number 1 suspect) or the fuel pump is defective

Re: Need some Help on this 4hp Evinrude

there is a notch screwed onto the intake (on my older ones) that only allows the adjustment so far. This 'tab' comes off and you are free to further adjust.

For the compression test: pull out the spark plugs. Insert the tester into one of the cylinders. Pull the rope until the gauge stops rising. Repeat for the other cylinder (assuming it's a twin motor).

The PSI should be over 60lbs. and within 10% of the other cylinder.... 80 lbs. would be ideal. And if it's over 110 lbs. or so, I would get a different tester.

Re: Need some Help on this 4hp Evinrude

Well Lehner,

Looks like you are the proud owner of a 1976 Evinrude 4hp.


***First check to make sure the vent cap or plug on the tank is open. If it is not open then the motor will run ok for a little bit and die or run poorly. The vent cap or plug has to be open to allow air to enter the tank so fuel can easily be pumped out of the tank by the fuel pump. If the vent cap or plug is closed then the fuel pump has to work against a negative system created in the tank, and you may get low or no flow from the tank.**** Make a long story short, make sure the vent cap/plug is open and try to start your motor.

Also check to see if the fuel pump bulb near the tank has the arrow pointing toward the motor and pumps up somewhat firm.


Here is a electronic parts diagram of your motor, so that will help you a bit.

http://www.boats.net/parts/search/BRP/EVINRUDE/1976/4606M 1976/parts.html

Here are some links, that are posted here on iboats, thanks to very awesome members who took the time to put them together

How to check for spark.(with a spark checker) about $6 at autozone (or similar store)...harbor freight store. You will also need a feeler guage to gap your spark plugs to 0.030 (feeler gauge is about $3 to 4 dollars)

- adjust the spark test to about 1/4 inches or so. It should be a good strong blue spark. (don't forget to ground the tester to the motor)

http://forums.iboats.com/showthread.php?t=294072

http://www.youtube.com/watch?v=lk70oyUEftY (general visual)

How to check compression:(remember to remove both spark plugs) can get for about $10 to 12 dollar at harbor freight or auto zone) auto zone will let you borrow one with a refundable deposit)

http://forums.iboats.com/showthread.php?t=391323

http://www.youtube.com/watch?v=PyCw4SiuT2I (gives you visual)

Carburetor adjustments

http://forums.iboats.com/showthread.php?t=167352

Carburetor cleaning instructions

http://forums.iboats.com/showthread.php?t=244013

Here is a picture of how the float should lay.




- Check the for spark on both cylinders.

- check compression on both cylinders

Please report back and some knowledgeable person will assist you!!

Good luck!!

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Re: Need some Help on this 4hp Evinrude

very informative post... must've taken a while to organize.

Re: Need some Help on this 4hp Evinrude

Your needle adjustments are to made on the water and don't run you engine faster than a high speed idle in a bucket. You might try elevating your gas tank to a level more like it will be on your boat. Those fuel pumps aren't meant to lift the gas very much. Sounds like you making progress though. Keep us posted on your findings. Rick.

Re: Need some Help on this 4hp Evinrude

Thanks for the help guys I haven't ahd the time I'd hoped for, so i haven't done that test yet. but yes I understand about vapor lock and how the plug has to be pulled. I have the motor upright like it is on the boat when it is in the bucket. (Didn't know not to trya nd push it too hard in the bucket tough so thanks for hat advice)

Re: Need some Help on this 4hp Evinrude

Checked the compression today, one read 61 the other read 65. So I'm happy to hear that the compression won't be a problem.

Re: Need some Help on this 4hp Evinrude

That is lower than I was hoping it would be. Once you get it running a good treatment of seafoam may help to bring it up. Rick.

Re: Need some Help on this 4hp Evinrude

Rick. said:

That is lower than I was hoping it would be. Once you get it running a good treatment of seafoam may help to bring it up. Rick.

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Yeah shouldn't it be closer to 80psi? I've yet to perform a spark test on it, but it does start so I'm not sure what it'll prove.

Re: Need some Help on this 4hp Evinrude

That would be better but not to worry. Different procedures and gauges produce different results. At least the two cylinders are very close in numbers which is a good thing. After I did a seafoam decarb on mine the compression improved by 15 to 20 lbs. Hopefully it will loosen up you rings as well. Your spark should jump 3/8ths. gap and be blue/white in color and really snappy. I think your problem is in the carb. though. Rick.